Abstracts from the New England Section of the AUA 2021

© The Canadian Journal of Urology TM : International Supplement, October 2021 Concurrent Scientific Session IV: Oncology II 34 Association Between Lymph Node Burden and Overall Survival Among Patients Treated with Adjuvant Radiation Therapy Following Radical Prostatectomy Syed N. Rahman, MD 1 , Thomas F. Monaghan, MD 2 , SoumLokeshwar, MD 1 , Tashzna Jones, MD 1 , Andrew G. Winer, MD 2 , Michael S. Leapman, MD 1 1 Yale School of Medicine, NewHaven, CT, USA; 2 SUNYDownstate Health Sciences University, Brooklyn, NY, USA Introduction: Although there is increasing evidence to support the use of adjuvant radiation therapy among patients with lymph-node positive prostate cancer after radical prostatectomy (RP), however it is unclear whether benefits persist for patients with high burdens of metastatic disease. We aimed to evaluate the association between the number of positive lymph nodes identified at the time of radical prostatectomy and lymph node dissection and overall survival after adjuvant androgen deprivation therapy (ADT) and radiation therapy (EBRT) versus ADT alone. Materials & Methods: We identified patients with lymph node positive (pT2-4N1M0) prostate cancer treatedwith RP in the National Cancer Database (2004-2017). The primary study objective was to compare overall survival among patients who received adjuvant ADT alone versus ADT+EBRT across numbers of positive lymph nodes identified (<3 versus ≥3). In addition, we compared survival across numbers of positive lymph nodes identified among patients receiving adjuvant versus salvage (>6month) radiation. We compared overall survival (OS) using multivariable Cox proportional hazards models adjusted for clinical and pathological characteristics including the number of total lymph nodes removed during PLND. Results: We identified 6,099 patients whomet inclusion criteria. After RP, 3267 patients (53.6%) received ADT alone and 2832 (46.4%) received ADT+EBRT. Patients treated with adjuvant ADT+EBRT were younger (60.9 vs 62.4 years), and a higher percentage of positive surgical margins (64.9% vs. 53.2%). However, patients receiving ADT alone had a higher mean PSA 22.4 vs. 21.2 ng/dl). Cox proportional hazards regression revealed that ADT+EBRT versus ADT alone was associated with improved OS (HR=0.65 [0.53-0.80] p<0.001) in the total cohort. This persisted at among patients with <3 positive lymph nodes identified (HR=0.61[0.48-0.79] p<0.001). However, among patients with >3 positive lymph nodes identified,ADT+EBRTwas not associatedwith improved survival compared with ADT alone (HR=0.65 [0.52-1.09] p=0.13). Receipt of salvage RT among patients with >3 positive lymph nodes treatedwith salvage radiation were associated with worse OS compared with adjuvant radiation (HR=2.08 [1.08-3.85] p=0.02). Salvage radiation was not associated with worse OS in those with <3 positive lymph nodes (HR=0.79[0.49-1.27] p=0.33). Conclusions: Although adjuvant ADT+EBRTwas associatedwith improved survival among patients with node-positive prostate cancer at the time of radical prostatectomy, we did not identify a survival benefit among patients with greater than three lymph nodes identified. Salvage radiation may be an alternative to adjuvant radiation below 3 positive lymph nodes identified. How Many Cores are Enough? Optimizing the Systematic Transperineal Prostate Biopsy Template Christian Schaufler, BS , Ryan Daigle, BS, Summit Singhaviranon, BS, Carl K. Gjertson, MD, Peter C. Albertsen, MD, Benjamin T. Ristau, MD UConn Health, Farmington, CT, USA Introduction: Most urologists use a 10-12 core systematic transrectal (TR) prostate biopsy template. However, a similar consensus template has not been reached for transperineal prostate biopsy (TP) regarding the optimal number and location of biopsy cores. We examined our institutional cohort to define an optimal systematic template for TP. Materials &Methods: We prospectively monitored our first 200 consecutive free-hand TP biopsies. Menwho were biopsy naïve (BN, n=117), had elevated PSAwith prior negative biopsy (PNB, n=18), and men on active surveillance (AS=65) were included.All underwent 20 core TPbiopsywith each core placed in a separate specimen container. 10, 12, and 16 core templates were designed a priori and compared within each patient to the 20-core standard ( Figure 1 ). The primary outcome was detection of Grade Group ≥ 2 (GG2) relative to detection of Grade Group 1 (GG1) prostate cancer. An historic cohort of 12 core TR biopsy (n=170) was used to compare prostate cancer detection between techniques. Sub-group analyses of BN men and men stratified by PSA density (<0.15 vs. ≥0.15ng/cc/mL) were performed. Results: ≥GG2 cancers were detected in 98 (49%, 20 core), 93 (47%, 16 core), 91 (46%, 12 core), and 82 (41%, 10 core, p=0.13) men. More ≥GG2 were detected in the 20 core compared to the 10 core template (49%v. 41%, p = 0.02). Additional cores did not result in increased GG1 detection (20 core: 35 vs. 10 core: 44, p = 0.09) reflecting improved detection of concomitant ≥GG2 with more cores sampled. There was no significant difference in ≥GG2 detection between an historic 12 core BN TR series (n=148) and the 12 core BN TP cohort (38% vs. 44.5%, p = 0.11). Among BN men, detection of ≥GG2 was similar to the overall cohort: 56 (48%, 20 core), 53 (46%, 16 core), 52 (45%, 12 core), and 47 (41%, 10 core, p=0.14). In men with a PSA density of <0.15ng/cc/mL, ≥GG2 was found in ≤ 25% of samples across all templates. Conclusions: A20 core TP systematic biopsy template demonstrated improved detection of ≥GG2 prostate cancer compared to a 10 core TP template. Increasing core number did not result in greater detection of GG1 tumors. Systematic templates with fewer cores may be feasible in patients with PSAdensity < 0.15 ng/ml/cc. We propose a 20 core systematic TP biopsy template against which future work including MRI-targeted TP biopsies can be compared. 33 18